In linguistics, pausa (Latin for "break", from Greek "παῦσις" pausis "stopping, ceasing") is the hiatus between prosodic units. Some sound laws specifically operate in pausa only; for example, certain phonemes may be pronounced differently at the beginning or end of a word when no other word precedes or follows within the same prosodic unit, as in citation form. This is the case with the final-obstruent devoicing of German, Turkish, Russian, and other languages, where voiced obstruent consonants are devoiced pre-pausa as well as before voiceless consonants; the opposite environment is relevant in Spanish, where voiced fricatives become stops post-pausa as well as after nasals.